The present invention relates to a rotary motion detector, and more particularly, to a rotary motion detector which produces a large signal while requiring only a small installation space.
Rotary motion detectors with an excitation assembly, an electrically conducting induction element and a sensor assembly are generally known in the art. The induction element is essentially formed as a hollow cylinder and rotatable about a rotation axis, with an inhomogeneous magnetic field being applied to the induction element by the excitation assembly. When the induction element rotates about the rotation axis, an eddy current is induced in the induction element. The sensor assembly measures a measurement signal that depends on the eddy current.
Rotary motion detectors of this type are described, for example, in German Pat. No. DE 100 08 765 C1 and French Pat. No. FR 1 232 969. In the rotary motion detector of FR 1 232 969, both the excitation assembly and the sensor assembly are arranged radially outside the induction element. The rotary motion detector of French Pat. No. FR 1 232 969 is therefore relatively compact, but produces only a comparatively small measurement signal. In the rotary motion detector disclosed in German Pat. No. DE 100 08 765 C1, either the excitation assembly or the sensor assembly are arranged radially inside the induction element. The corresponding other assembly, i.e. the sensor assembly or the excitation assembly, is arranged radially outside the induction element. The rotary motion detector of German Pat. No DE 100 08 765 C1 therefore requires a relatively large installation space.
It would therefore be desirable and advantageous to provide an improved rotary motion detector, which obviates prior art shortcomings and is compact while still producing a large measurement signal.